All Periods erased when I put I was pregnant?

Amber • Mommy to Bryce 12/2/14 & Myla 5/29/17. Expecting baby #3 December 2019!
When I put I got a positive pregnancy test yesterday glow erased all of my past periods! Why? Did this happen to anyone else? It also said I skipped a period when AF isn't due until Thursday. Did this happen to anyone else?